Ultrasmall CeO_2-x@β-CD nanoparticles with pH-dependent prooxidant activity and doxorubicin loading/release capability

In this article, we propose multifunctional ultrasmall (2-3 nm) CeO_2-x@β-CD nanoparticles (NPs) as combined nanozymes and potential drug delivery platforms for anticancer drugs. The CeO_2-x@β-CD NPs demonstrate high peroxidase-like and oxidase-like activities towards 3,3',5,5'-tetramethylbenzidine (TMB) and thiol-oxidizing ability. Both peroxidase-like and anticancer drug doxorubicin (DOX) release properties of CeO_2-x@β-CD NPs are pH-dependent, being more pronounced in acidic environments, ensuring high potential selectivity of the antitumor action of CeO_2-x@β-CD NPs for cancer cells whose pH is less than that of non-cancer ones. The chemisorption of DOX in β-CD cavities provides a steady, long-lasting release of the chemotherapeutic drug, opening potentially the way for the development of CeO_2-x NP-based agents for long-term cancer treatment.